Advancements in horizontal drilling and hydraulic fracturing (fracking) have allowed access to untapped natural gas reserves in shale formations. Although the health consequences of shale gas extraction activities have not been fully explored, shale gas extraction wells may co-occur with population centers. The Barnett Shale, near the Dallas/Fort Worth (DFW) metroplex, is the largest shale play in Texas and the nation's most developed, with over a decade of natural gas production. Although there are overwhelming environmental and public health concerns regarding health effects related to air and water pollution resulting from shale gas extraction drilling activities, few peer-reviewed systematic investigations of adverse health effects among residents in communities near shale gas extraction wells exist. There is epidemiologic evidence that environmental exposures, such as air and water pollution, may increase the risk of adverse pregnancy outcomes, including preterm birth and low birth weight (LBW), both major drivers of infant mortality. However, there are no such investigations among women living near drilling activities in Texas. Therefore, we will conduct an epidemiologic study, using a retrospective birth cohort, to examine the relation between maternal residential proximity to shale gas extraction drilling activities and adverse pregnancy outcomes among women in communities near the Barnett Shale. We hypothesize that living near shale gas extraction drilling activities increases women's risk of having poor pregnancy outcomes. The first aim will examine the geographic distribution of shale gas extraction wells in the Barnett shale in relation to Texas water district boundaries. The second aim will examine the associations between maternal residential proximity to shale gas extraction drilling activity in the Barnett shale and pregnancy outcomes (birth weight, preterm birth, small-for-gestational age, and fetal loss) using regression analyses, and adjusted for appropriate covariates. This study will address public concerns regarding potential hazards experienced by communities near shale gas extraction drilling sites. More specifically, the results will inform both the public and the research community concerning potential adverse reproductive health effects in these communities. This investigation will also serve as a starting point and provide direction for future comprehensive investigations of chemical exposures experienced by individuals living in communities near the Barnett Shale. Identifying potential pregnancy risks experienced by women in these communities will inform NIEHS' mission of discovering how the environment affects people and promoting healthier lives.